Question

1.A worker pulls horizontally on a crate across a rough horizontal surface, causing it to move forward with constant velocity. Force A is the force exerted by the worker and force B is the force of friction due to the surface. What is the relationship between A and B?
A = B

A< B

A > B

2. In a color picture tube, an electric field exerts a net force of magnitude 1.60 × 10-13 N on an electron. The rest mass of an electron is 9.11 × 10-31 kg. What is the electron's accceleration?

1.76 × 1017 m/s2

1.96 × 1024 m/s2

1.45 × 1043 m/s2

1.60 × 10-13 m/s2

Answer 1

1. Answer:

The relationship between Force A and Force B is given as:

A = B

Explanation:

To produce acceleration to a body, an unbalanced force must be applied. Meaning that a Force must be applied to the body greater than that of Force of Friction.

In our case, a Force A is exerted on the crate which is moving with a constant velocity. As there is no acceleration, the force applied must be equal to the force of Friction B.

2. Answer:

The electron's acceleration is 1.756 x 10¹⁷ ms⁻².

Explanation:

Electric field exerts a Force on the electron given as:

F = 1.6 x 10⁻¹³ N

Rest mass of electron = 9.11 x 10⁻³¹ kg

According to newton's 2nd law of motion, a net force F applied on the electron must produce an acceleration 'a' which is directly proportional to the Force and inversely proportional to the rest mass of the electron given as:

a = F/m

a = (1.6 x 10⁻¹³)/(9.11 x 10⁻³¹)

a = 1.756 x 10¹⁷ ms⁻²